Might it be because threads like these often cause toxic, rude, unproductive, and generally tribal discourse in the comments?

Looking around the comment threads, I certainly don't see a lot of intellectual curiosity being stimulated or minds being expanded. I see a lot of dogmatic accusations, hyperbolic bemoaning-the-downfall-of-civilization, and general "how could you possibly believe that?!"-toned rudeness. Not our finest hour.